1. Field of the Invention
This invention pertains generally to electrical audio signal processing systems and devices, and more particularly to electro-acoustic audio transducers such as housed microphones that are supported upon a boom stand and counterbalanced by stable and acoustically neutral counterweights. In a most preferred manifestation, the present invention relates to acoustically inactive counterweights that are readily manually attached and detached from booms on an electro-acoustic microphone stand.
2. Description of the Related Art
In many settings such as but not limited to broadcast or live musical performances, electro-acoustic microphones and other apparatus are often attached to an at least partially horizontally extending arm, referred to as a boom, that is supported by a vertical support or stand. Most commonly, the item to be supported will preferably be easily relocated, as will the stand or at least the boom. This ability to provide a relatively adjustable and easily relocated support is in great demand. Frequently, a plurality of these boom stands will be required, such as, for exemplary purposes but not limited thereto, in the case of a musical or theatrical performance where different performers or different parts of a stage are preferred to be either illuminated or coupled into an audio system.
Depending upon the particular item to be supported, the boom stand may have several requirements which must be met to perform satisfactorily. Among these, one common requirement is the ability for a person to readily and rapidly reposition the boom, and then subsequent to the repositioning, anchor the boom into a new fixed position. This ability to readily and rapidly reposition the boom permits the stand to be placed at a convenient location along the ground or floor, without great care in the precise positioning. Once the base is located, then the boom arm may be moved into proper alignment.
While the application for the boom stand will to some degree potentially affect the various dimensions and some of the configurations not only of the base, but of the stand as well, including such things as particular lengths or dimensions of the base and the boom, most desirably a boom stand will offer substantial flexibility in both application and physical arrangement and positioning. This flexibility is a desirable part of the benefits of such a stand, which is in part what separates such a stand from a fixture or anchored support.
Since the boom may extend some distance from the base, it is generally desirable to incorporate significant mass into the base, to provide some measure of stability during movement or adjustment of the boom and subsequent thereto to best maintain the location of the boom. Unfortunately, in the prior art this often led to the use of a large and very massive base, typically of disc, slightly domed, or similar shape. Such a base is not readily transported, nor can it be used or stored in close arrangement with other bases. Consequently, it is not possible to tightly and compactly arrange, use or store a plurality of similar stands.
To provide more compact storage and lighter weights, a number of designers have resorted to tripod stands. By providing a plurality of longer legs, the legs may be manufactured in much lower weight or mass, while still providing good stability against tipping. Unfortunately, these stands also have drawbacks. First and foremost, the tripod legs, to avoid the need for substantial mass, must be relatively long. Long legs in turn form a serious hazard for anyone passing near to the boom stand. In the event a boom stand is accidentally knocked over, the item supported thereon may be destroyed. In the case of the performing arts, the microphones that are supported thereon may cost thousands of dollars to replace. Furthermore, the disruption to a performance when a stand is accidentally toppled is highly undesirable.
Consequently, there are trade-offs that have been required with many of the prior art boom stands in either portability or stability that are undesirable. Either the stand is light and unstable, light and in the way and prone to being accidentally toppled, or heavy and difficult to handle, move about, and store.
Even where the vertical support is stable enough to support an unbalanced device some horizontal distance from the vertical support, another challenge arises in the coupling between boom and vertical support. In many of the prior art stands the connection between the boom and the vertical support can weaken or slip, causing the boom to lower on the side with the device. This sagging leads to undesirable movement away from the musician or instrument, which can lead to complete loss of adequate signal coming from this microphone or to a loss of selectivity of sound being received by the microphone.
This sagging arises due to an inadequate coupling between boom and stand. Heretofore in the prior art, one such coupling was a simple connection using a screw or the like to urge two flat surfaces together, or using the screw in a manner similar to a set screw to bite into an opposed surface. Two exemplary patents, the teachings and contents which are incorporated herein by reference, are U.S. Pat. No. 5,154,381 by Malinao, entitled “Microphone boom holder”, which illustrates a prior art weak pivot, with a fixed counterweight; and U.S. Pat. No. 5,739,447 by Hoshino, entitled “Attachment and detachment of a weight to a boom cymbal stand”, which illustrates a thumb screw to prevent rotation of boom, a tripod stand for portability, and a manually attached and detached fixed weight.
This type of connection has almost no resistance to pivotal forces at the end of the boom, since the measure of forces upon an arm are calculated by not only the force applied, but also by the distance from the point of rotation. Consequently, when even a small force is applied at a great distance such as at or near the end of a boom arm, the force is magnified by the multiple of relative distance from pivot. Said another way, a first force applied at ten times the distance from a pivot as a second point would require ten times the first force to be applied in an opposite direction at the second point to cancel the first force. In the case of a small flat, knuckle, or set screw located at or adjacent to the pivot, such as found in the Malinao patent, this knuckle may be hundreds or even thousands of times closer to the pivot than the end of the boom, and consequently require hundreds or thousands of times the force to prevent rotation about the pivotal axis. The end result of this inadequate coupling between boom and stand is movement of the boom, which may in turn lead to the device being located in a position not balanced directly over the vertical support, and therefore require all too frequent manual readjustment and alignment. Additionally, this imbalance provides a certain amount of risk of tipping the vertical support, which can lead to destruction of sensitive microphones, as well as harm or damage to surrounding equipment and people.
As a result, and as is known in the industry, even minor forces of only a few pounds at the end of the boom overcome the resistance at the knuckle, since these few pounds require thousands of pounds of force at the knuckle to stop such rotation. The few pounds of force cause the boom to realign undesirably. One way to overcome this deficiency of the prior art couplings between boom and stand is to provide a higher-quality coupling, such as illustrated by the present inventor in U.S. Pat. Nos. 7,207,532; 7,635,109; and 7,819,367; the contents and teachings of each which are incorporated herein by reference. These patents illustrate a particularly stable stand that can support very large loads from the end of the boom, without any sagging and with an improved massive base that enables relatively larger off-balance loads to be safely supported by the stand.
However, there are many stands that have already been produced and placed into service that do not have the features found in the stands designed in accord with the present inventor's patents. Another way to at least in part overcome the weak holding force found in many of the prior art couplings is to provide a more precise counterweight on an end of the boom arm opposite to the microphone or other device. If the counterweight creates an equal and opposite torque to that created by the microphone, then there is no net rotary force applied to the boom. This means that there is no tendency for the boom to rotate, meaning that more modest prior art couplings can still support a microphone properly.
However, with this counterweight comes a new set of challenges. One of these is the way the counterweight is attached to the stand. Most commonly, this is accomplished with a set screw or the like, which permits a fixed weight to be slid along the portion of the boom on the opposite side of the stand connection, distal from the microphone end. The weight can then be moved to compensate for heavier and lighter microphones or other devices. Furthermore, if the boom is adjusted to extend farther from the stand on the microphone side, the weight may also be moved to again zero the rotary forces about the coupling between boom and stand. Since the weight is intended to slide along the boom, and since the boom will generally not be a perfect cylinder, there must also be some space or gap between the inside bore of the weight and the outside diameter of the boom to accommodate these variances. This also means that the weight cannot fit tightly onto the boom, except for by the use of a set screw. Over time, the set screw will damage the boom, and will also tend to loosen, just as the coupling between boom and stand tends to loosen. As a result, this type of weight loses efficacy, and may also damage or destroy the boom. If the set screw loosens, there will be a great propensity for acoustic vibration, which can destroy the function of the microphone and stand. Because of the limited engaging surfaces, which comprise the tip of the set screw and a small line of contact directly opposite of the set screw tip, there may also be a tendency in some stands to develop destructive acoustic vibrations even when the set screw is secured. Furthermore, a wrench is required to tighten or loosen the set screw, which must occur before adjusting the position of the counterweight. As a result, these types of weights are normally affixed once and often never adjusted again.
Other artisans have coupled weights using other techniques. In the Hoshino patent incorporated by reference herein above, a static weight is provided that quickly attaches and detaches to provide counterbalance for a cymbal. Undesirably, this weight is relatively complex, thereby requiring greater cost and incorporating a greater chance of failure or undesirable resonances, and still provides only for a boom with or without the single weight. Another exemplary patent, the teachings and contents which are incorporated herein by reference, is U.S. Pat. No. 5,611,508 by Palmero, entitled “Horizontally adjustable microphone support”. This patent describes a threaded-on counterweight that is adjustable by how far onto the threaded rod the weight is rotated. However, there is nothing to load or lock the threads, meaning the device will tend to spin about the threads, and self-adjust. In addition, since there is no solid connection between the weight and the boom, the connection there between will be prone to vibrating undesirably.
Beyond the music industry, booms or similar apparatus are known that extend horizontally. However, these booms have very different requirements and objectives than those required for an electroacoustic device. Because of the lack of concern about acoustic energy or acoustic coupling, most of these devices use weights that are free to rattle about. An exemplary patent, the teachings and contents which are incorporated herein by reference, is U.S. Pat. No. 3,028,133 by Craig, entitled “Baby bottle holder”. This patent describes a set of screw-on counterweights. These weights screw over a threaded shaft, but the weights are free to vibrate against each other and the shaft, making this apparatus completely unacceptable for use with an electroacoustic device.
Others use cables and other apparatus that can also resonate or vibrate. An exemplary patent, the teachings and contents which are incorporated herein by reference, is U.S. Pat. No. 3,783,262 by Pile, entitled “Portable surgical lamp”. This patent describes a cable-connected counterweight as a part of an undesirably large and exposed apparatus. The cable will create an undesirable resonance at a frequency determined by the cable length and tension, will be awkward to transport, and may be dangerous if accidentally snagged and swung about.
Others have structures that are known exactly, such as for lights and the like, and these apparatus also control the movement to keep the counterweight and fixture balanced. An exemplary patent, the teachings and contents which are incorporated herein by reference, is U.S. Pat. No. 3,789,213 by Sonneman, entitled “Counterbalanced lamp”. This patent describes a fixed counterweight, made possible by the known fixed weight of the light fixture and the novel pivoting structure that keeps the weight and light fixture balanced for zero net torque. Other similar exemplary patents, the teachings and contents which are incorporated herein by reference, are U.S. Pat. No. 3,994,464 by Perbal et al, entitled “Internally wired counter-balanced bracket”; U.S. Pat. No. 4,364,535 by Itoh et al, entitled “Counterbalance mechanism for laser knife device”; U.S. Pat. No. 4,782,428 by Lowell et al, entitled “Collapsible fluorescent light for photography”; and U.S. Pat. No. 3,790,773 by Sapper, entitled “Lamp with an articulated support”.
Yet others use basic fastener attached counterweights that require a pair of tools to secure, release, or adjust the weights. One exemplary patent, the teachings and contents which are incorporated herein by reference, is U.S. Pat. No. 3,486,514 by Prescott, entitled “Canopy support”. This patent describes an umbrella support using a set of counterweights held onto a shaft by a pair of nuts surrounding the weights. Another exemplary patent, the teachings and contents which are incorporated herein by reference, is U.S. Pat. No. 5,126,928 by Hughes, entitled “Mobile boom-mounted shop light”. This patent describes a counterweight using set-screw attached collars to capture the weights.
In addition to the foregoing patents, Webster's New Universal Unabridged Dictionary, Second Edition copyright 1983, is incorporated herein by reference in entirety for the definitions of words and terms used herein.